Cylindrical beam cathode ray tube



Oct. 9, 1962 R. A, FRYKLUND CYLINDRICAL BEAM CATHODE: RAY TUBE 2 Sheets-Sheei'I 1 Filed Feb. 9, 1949 mm SNI ATT /v Y Oct. 9, 1962 R. A. FRYKLUND CYLINDRICAL BEAM cATHoDE RAY TUBE 2 Sheecs-Sheeafl 2 Filed Feb. 9, 1949 PULSE nite 3,058,027 Patented Oct. 9, 1962 hee 3,058,027 CYLIWDRICAL BEAM CATHDE RAY TUBE Robert A. Fryltlnnd, Somerville, Mass., assigner to Raytheon Company, a corporation of Delaware Filed Feb. 9, 1949, Ser. No. 75,479 17 Claims. (Cl. 315-18) This application relates to electron discharge circuits and more particularly to a system whereby signals may be simultaneously received from all directions and presented on a cathode ray tube.

In prior systems, used principally for underwater sound-echo ranging applications, wherein following the transmission of a pulse of supersonic energy, omnidirectionally through the water, and the receiving system listened in different directions successively in order to present an echo, it was necessary to sweep around the 360 of azimuth listening in each direction successively, and presenting the informatori, for example, on a cathode ray tube. This shifting of the direction of listening had been accomplished by a mechanical or electronic switching device which produced noise at suitable speeds of rotation of the switching mechanism, which noise interfered with the reception of weak signals or distant echoes.

Furthermore, since the listening mechanism was rotated through many cycles during the time between successive pulses from the transmitting device in order to produce substantially simultaneous coverage of the area being scanned, it was necessary that the length of the transmitted pulse be at least equal to, and preferably sever-al times greater, than the time required for one revolution of the listening device, to insure the reception of echoes of suicient time duration such that no echo will be entirely received during the time when the listening device is pointed in some other direction than that from which the echo arrived. j Accordingly, it is an object of this invention to produce a system which will listen to echoes being received from all directions simultaneously thus eliminating the possibility of entire signals arriving when the listening device is pointed in other directions from that at which the echo arrived.

A further object of this invention is to produce a device which will simultaneously receive and present all signals from all directions regardless of the width of the transmitting pulse.

Still another object of this invention is to provide a device wherein noise generated due to directional switching of the listening device is eliminated.

A further object of this invention is to produce an electron discharge device having a cylindrical electron beam.

j Other and further objects of this invention will be apparent as the description thereof progresses, reference being had to the accompanying drawings wherein:

FIG. l represents a longitudinal cross-sectional view of a cathode ray tube taken along line A-A of FIG. 2,

FIG. 2 represents a cross-sectional View of the cathode ray tube taken along section line B-B of FIG. 1, and

FIG. 3 represents a block diagram of a receiving circuit utilizing the invention.

Referring now to FIGS. l and 2, there is shown a cathode ray tube 1, comprising an evacuated envelope 2 made of glass which contains therein an electron gun 3 and a dluorescent screen 4. The electron gun contains a cathode 5 consisting of an annular ring of metal Whose crossgsectional area is substantially a half circle the ends of said half circle lying in a plane which is perpendicular to the axis of said annular ring. The convex surface of said half circle is coated with an electron emissive substance, said convex surface being the surface of the ring nearer the fluorescent screen 4. The concave surface of said cathode ring 5 which forms an annular trough, contains a heater coil 6 therein, which is insulated by being surrounded by a ceramic compound 7, for example, Alundum.

The cathode structure is supported by a plurality of stiff wires 8 connected thereto and imbedded in a hollow cylindrical rod 9 of glass which extends approximately half way from the cathode 5 to the screen 4 along the axis of the cathode ray tube 1. The inner end of the rod 9 is sealed off and the outer end is connected to the envelope 2 forming a part thereof, whereby the vacuum inside the cathode ray tube is maintained. The leads from heater 6 are brought out through the glass envelope 2 to a source of heater voltage designated H-H.

Adjacent the cathode structure 5 and between the cathode and the target 4 there is positioned a beam forming grid 10 comprising a pair of concentric rings lying in substantially the same plane dening an annular space therebetween which is directly in line with the electron emitting surface of the cathode 5 and the target 4. By the application of a suitable potential between the cathode 5 and the grid 10 electrons may be passed through the grid 10 from source 5, or rejected, as desired.

Adjacent said grid 10 and between said grid 10 and the screen 4 and surrounding said center rod 9, there is shown an annular control grid network 113:. The control grid network comprises two supporting mica rings 11 and 12 concentric with the axis of cathode ray tube and in the same plane and defining therebetween an annular space of substantially the same diameter, and in registry with, the annular space of the grid 10 Stretched across said annular space deiined by said mica rings 11 and 12 are a plurality of radially extending Wires of the grid network 13, for example, as used in the particular embodiment shown herein, 48 in number. As shown more particularly in FIG. 2, each grid member 13 consists of a wire one end of which is bonded, for example, by a ceramic cement to the outer mica ring 11. The wire extends radially inward across the inner mica ring 12 and around a tooth cut on the inner edge of the mica ring 12. The same wire then extends radially outwardly across both rings 12 and 11 and through the envelope 2 thus presenting an external terminal for each grid member I13 whereby a signal may be placed on each member without any ei'ect on the other grid members 13. Thus it may be seen that by placing sufciently negative signals on any of the grid members 13, electrons may be prevented from passing from the cathode 5 to the target 4 in the area immediately adjacent any of the grid members 13. Due to the multiplicity of wires 13, the control grid structure is supported entirely by the passing of said wires 13 through the envelope 2. The purpose of the mica disks 11 and 12 is to preserve the relative spacing between the wires 13.

Adjacent the control grid structure 13 and between said structure and the target 4 there is shown a focusing anode 14 comprising a pair of concentric cylindrical sleeves coaxial with the inner glass rod 9 with the ends of the cylinder sleeves lying in substantially the same planes. The ends of said sleeves 14 are attached to flat rings 15 which extend toward each other. The annular space between the rings 15 in conjunction with the sleeves 14 will, upon the application of suitable potentials to the tube 1 produce a sharply defined cylindrical electron beam. The innermost of the sleeves 14 is supported by Wires 16 attached thereto and imbedded in the circular ,glass rod 9. The outer of the sleeves 14 is supported by wires 16 imbedded in the outer envelope 2. The dameter of the annular space between the rings 15 is substantially equal to that of the diameter of the annular cathode ring 5 and in registry therewith such that electrons may pass in a lstraight line from the electron emissive surface of the cathode 5, through the suppressor grid 10, the plurality of grid wires 13 and the space between the rings 15 Iand strike the .target 4.

Adjacent the focusing anode structure 14 and between said structure and the screen 4 there is shown an annular accelerating anode structure 17 substantially similar to the focusing anode structure 14 but minus the rings 15. The annular space between the sleeves of the accelerating yanode structure registers with the previously mentioned annular spaces to allow the straight line passage of electrons therethrough. The accelerating anode structure is supported by rods 16 similar to the manner in which focusing anode structure is supported.

Adjacent said iaccelerating anode structure 17 and between said structure 17 and the screen 4 there is shown a pair of beam delleotion electrodes comprising two truncated cones. The inner cone 18 of the deflection plates has a base diameter approximately equal to the diameter of the innermost of the accelerating sleeves 17 with the virtual lapex of the cone extending toward the screen 4. The outer vdeflection plate 19 lcomprises a trun cated cone with the section at the point of truncation having a diameter equal substantially to the outermost of the accelerating anode sleeves: 17. The elements of the outer truncated conical deflection plate 19 diverge toward the screen 4. The deflection plates 18 and 19 are supported by wires 16 similar to the method previously described. Inside of the envelope surrounding the screen 4 is a coating 20 of conductive material such as aquadag.

To suitably operate the cathode ray tube 1, D.C. p'otentials are applied to the various electrodes, for example, as follows:

A resistor 21 is connected from ground to a positive potential of 2000 volts which is connected to the aquadog coating on the inner surface of envelope 2. The outer deection plate 19 is connected through a load resistor 22 to ground. It is across this resistor 22 that the input from 4the sweep circuits is developed. The inner deflection plate 18 is connected to a variable tap on the resistor 21 which may be, for example, a few volts positive with respect -to ground. Accelerating anode 17 is connected to ground. A second voltage divider network 23 is connecte-d between yground and a source of negative potential of, for example, minus 2200 volts. The focusing anode 14 is connected to a variable tap of the voltage divider network 23 having a potential of the order of minus 900 volts. Each of the grid wires 13 is connected through a separate grid resistor 25 to an annular ring 25a which in turn is connected to a variable tap on the voltage divider network 23 having a potential of the order of minus 2150 Volts. The suppressor grid 10 is connected to a variable tap on the voltage divider network 23 having a potential of the order of 2000 volts. The cathode 5 is connected to a tap on the voltage divider network 23 having a potential of minus 2000 volts. With the foregoing potentials applied to the cathode ray tube 1 a circle will appear on the screen 4 whose intensity may be governed by the potential on the suppressor grid 10 and by the potential on the control grids 13. and whose definition may be adjusted by the potential yapplied to the focusing anode 14. The diameter of the circle is governed by the potential between the deflection plates 18 and 19. The application of a sawtooth voltage between these `deflection plates will cause the diameter of said circle to increase linearly.

Now referring to FIG. 3 there is shown a circuit utilizing this tube. A sound reception device 26 which in this particular embodiment contains 48 circularly disposed omnidirectional signal receiving transducers 27, is connected to a delay linelens system 28 wherein the signals received by each of the transducers 27 are phased by the delay system such that 48 different outputs are obtained, one for each 71/2" of azimuth direction of the receiving device 26. The operation of lens system 28 is disclosed in more detail in copending application Serial No. 14,017, filed March 10, 1948, now Patent No. 2,786,193, issued March 19, 1957. Each of these outputs is fed through a separate amplifier 29 to a separate grid 13 of the cathode ray tube 1. The cathode ray tube is adjusted by means of the D.C. potential on the suppressor grid 10 and the control grids 13 so that no electrons strike the target 4 in the absence of a received signal in the transducer 26. When a signal is received from any direction it is transmitted from the transducer 27 through the delay line lens system 28, and one of the ampliers 29, depending on the direction from which the signal was received, to a grid 13 of the cathode ray tube causing that portion of the cylindrical electron beam controlled by said grid to be passed to the screen 4, during every positive half cycle of the received signal, thus creating a bright spot on the target 4 whose direction from the center of the target is indicative of the direction of the signal received.

In practice a strong pulse of energy is sent out from a pulse transmitter 30 through a transducer 31 in all directions. Said transmitter 30 at the same time triggers a sweep generator 32 to apply a linear saw-tooth sweep voltage to the deflection plates 18 and 19 causing the circular presentation on the screen 4 to slowly expand. Echoes will then be received from targets in the surrounding water which will `be Itransmitted through the transducer 26 to the delay network 28 and the amplifiers 2 9 to the cathode ray tube. The distance that any particular spot on the scope is from the center of the screen 4 will indicate the distance of the target in the water from the transducer 26. Thus it may be seen that by use of the cathode ray tube described herein there may be produced a ysystem which, immediately following the transmission of a pulse into the water, will listen in all directions simultaneously and immediately present all received echoes for display on the cathode ray tube screen. Moreover, since there is no switching involved the internal noise level will be extremely low thus permitting the ready reception of weak signals.

This completes a description of the illustrated embodiment of the invention. However, many modifications thereof will be apparent to persons skilled in the art, for example, a point source of electrons could be used which could be suitably expanded and formed into a cylindrical beam rather than use an annular cathode as an electron source. Further, the suppressor grid might be eliminated and various voltages and other configurations of the electrodes be substituted for those shown with the same resultant cylindrical beam. Also, the beam could be in the form of a flat plane rather than cylindrical, and

the presentation on the screen could be in Cartesian coordinate rather than in polar co-ordinates as shown herein. Moreover, the system is not necessarily limited to underwater -sound applications but may readily be applied to radar, radio direction finding and other navigational systems. Accordingly applicant does not wish to be limited to the specific details of the invention illustrated and described hehein except as defined in the appended claims.

What is claimed is:

1. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, means for directing said beam to a target, and a plurality of grids, said grids controlling substantially different elements of said beam.

2. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a beam having a component moving axially thereof, means for directing said beam to a target to produce a pattern thereon, and a plurality of conductive grids insulatedly supported with respect to each other, said grids controlling substantially diierent elements of said beam.

3. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, and a plurality of grids, said grids controlling substantially different elements of said beam.

4. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, comprising a series of electrodes having cross-sectional areas comprising disks containing annular apertures therein, means for directing said beam to a target to produce a circular pattern thereon, and a plurality of grids, each grid controlling an element of said cylindrical beam.

5. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, means for directing said beam to a target to produce a circular pattern thereon, a plurality of grids, each grid controlling an element of said cylindrical beam, and means for varying the diameter of said cylindrical beam.

6. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, comprising a series of electrodes having cross-sectional areas comprising disks containing annular apertures therein, means for directing said beam to a target to produce a circular pattern thereon, a plurality of grids, each grid controlling an element of said cylindrical beam, and means for varying the diameter of said cylindrical beam.

7. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, means for directing said beam to a target to produce a circular pattern thereon, a plurality of grids each controlling an element of said cylindrical beam, and means for varying the diameter of said cylindrical beam, comprising a pair of concentric deflection plates.

8. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam having a component moving axially thereof, comprising a series of electrodes having cross-sectional areas comprising disks containing annular apertures therein, means for directing said beam to a target to produce a circul-ar pattern thereon, a plurality of grid-s each controlling an element of said cylindrical beam, and means for varying the diameter of said cylindrical beam, comprising a pair of concentric conical deection plates.

9. In combination, a signal translating device having a plurality of outputs, each output producing a signal in response to reception of a signal from a different direction by said translating device, and an electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam, and a plurality of grids each controlling an element of said cylindrical beam, each of said grids being connected to an output from said translating device.

10. In combination, a signal translating device having a plurality of outputs, each output producing a signal in response to reception of a signal from a different direction by said translating device, and an electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam, means for directing said beam to a target to produce a circular pattern thereon, and a plurality of grids each controlling an element of said cylindrical beam, each of said grids being connected to an output from said translating device, whereby signals from different directions appear as bright spots on different segments of said circular pattern.

11. In combination, a signal translating device having a plurality of outputs, each output producing a signal in response to reception of a signal from a different direction by said translating device, and an electron discharge device comprising a source of electrons, means for forming electrons from said source into a hollow cylindrical beam, comprising a series of electrodes having crosssectional areas comprising disks containing annular apertures therein, means for directing said beam to a target to produce a circular pattern thereon, a plurality of grids each grid controlling an element of said cylindrical beam, each of said grids being connected to an output from said translating device, whereby signals from different directions appear as bright spots on different segments of said circular pattern and means for varying the diameter of said cylindrical beam, comprising a pair of concentric deflection plates.

l2. An electron discharge device comprising means for producing a plurality of electron beam elements, means for forming said beam elements into a hollow substantially cylindrical beam having a component moving axially thereof, means for directing said beam to a target to produce a substantially circular pattern thereon, and a plurality of grids, each grid controlling a different element of said beam.

13. An electron discharge device comprising means for producing a hollow substantially cylindrical beam having a component moving axially thereof, means for directing said beam to a target to produce a substantially circular pattern thereon, and a plurality of grids, each grid controlling a diiferent element of said beam.

14. An electron discharge device comprising means for producing a hollow beam having a substantially circular cross section and having a component thereof moving substantially axially thereof, means for directing said beam to a target to produce a pattern thereon, and a plurality of grids, each grid controlling a substantially different element of said beam.

15. In combination, a signal translating device having a plurality of outputs, each output producing a signal in response to reception of a signal from a different direction by said translating device, and an electron discharge device comprising means for producing an electron beam having a plurality of elements, and a plurality of grids, said grids controlling different elements of said beam, said grids being connected to different outputs of said translating device.

16. An electron discharge device comprising a source of electrons, means for forming electrons from said source into a beam having a com-ponent thereof moving axially of said device, means for directing said beam to a target to produce a pattern thereon, and a plurality of conductive grids insulatedly supported with respect to each other, said grids controlling substantially dilferent elements of said beam and adjacent pairs of said grids mutually controlling elements of said beam passing therebetween.

17. An electron discharge device comprising means for producing a plurality of electron beam elements, means for forming said beam elements into a hollow substantially cylindrical beam having a component moving axially thereof, means for directing said beam to a target to 'Z produce a substantially circular pattern thereon, and a plurality of grids, each grid controlling a different element of ysaid beam and adjacent grids mutually controlling elements of said beam passing therebetween.

References Cited in the le of this patent UNITED STATES PATENTS Sukumlyn Mar. 31, 1936 Karolus May 28, 1940 3 Anderson June 15, Iams June 22, Rhea Feb. 11, Beniof Dec. 30, Varian Apr. 5, Wathen et al. Apr. 5, Newbold May 31, Schuck June 21, Rajchman Jan. 17, 

